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Novel Possibilities by Cationic Ring‐Opening Polymerisation of Cyclodextrin Derivatives: Preparation of a Copolymer Bearing Block‐Like Sequences of Tri‐ O ‐methylglucosyl Units
Author(s) -
Adden Roland,
Bösch Andreas,
Mischnick Petra
Publication year - 2004
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200400192
Subject(s) - cationic polymerization , chemistry , polymer chemistry , copolymer , polymerization , dichloromethane , cyclodextrin , hydrolysis , ring opening polymerization , proton nmr , organic chemistry , polymer , solvent
Summary: Equimolar mixtures of O ‐permethylated and O ‐perdeuteromethylated cyclodextrins were submitted to cationic ring‐opening polymerisation (CROP) with Et 3 OPF 6 or BF 3 · Et 2 O as initiator in dichloromethane. Reaction started after an incubation time and yielded a polymeric product, which was partially degraded again during competing chain transfer reaction. Average block length was determined by ESI‐MS after partial methanolysis and was found to be close to the theoretical value of 14 for β ‐cyclodextrin in the early stage of the reaction, but decreased to 2–5 during further chain transfer reactions accompanied by an equilibration of α ‐ and β ‐configurated glucosidic linkages to a ratio of 64:36. Molecular weight was estimated from end group analysis and GPC to reach about 29 000 as a maximum. From 31 P NMR spectra of the initiator it was obvious that PF 6 −is partly hydrolysed to PO 2 F 2 2−under participation of the glass surface.